Election - Facts, claims, spin

The claims are all too familiar. You can't trust Labour not to spend and tax and borrow say the Conservatives. You can't trust the Tories with the NHS say Labour.

The facts and the claims and the spin that underpin them are new, though, and they matter.

What's also different from previous elections is the state of the public finances. Britain still has a massive deficit and growing debts so it is right that all parties should be heavily scrutinised to check they're being honest with voters about what spending they might cut, or what taxes they might increase if they get into power after May.

The Tories have released a headline figure - over £20bn - for what they say are spending commitments Labour have already made for next year. They won't show us how they reached that figure until later today when they will publish an 80 page dossier of what they call Treasury opposition costings.

It's important to be clear what this is and what it is not. The costing have been made by independent Treasury officials but - and it's a big but - what they've costed are political assumptions made by Tory advisers. Labour will dispute the detail and they say that all parties should have all their promises costed by the independent Office for Budget Responsibility. The chancellor will reply that he's only doing what his Labour predecessor did at the last election.

Standby for them to repeat the trick first used so successfully by John Major in 1992 - calculating the alleged "tax bombshell" which every household faces under a Labour government. The figures and the involvement of the Treasury are designed to give spurious credibility to what is at root a partisan assault on their opponents.

Once the smoke clears after the inevitable battle about whose assumptions are right what will matter is what impression is left. The Tories' aim is to convince voters that Labour are incontinent when it comes to public money - unable to control themselves whatever they may say.

Over the weekend Labour produced their own dossier of facts and claims. They compiled already published official data showing the number of targets that the NHS is now missing under the Tories. The picture, as the BBC has regularly reported, is of a system under very real pressure which could struggle to cope if there's a cold winter or a norovirus epidemic.

They too like to use official cover to make brazen claims about their opponents. Labour's first election poster claims that the Tories want to cut public spending to 1930s levels when, they add, there was no NHS.

Now it's true that the OBR forecast that under Tory plans spending would drop to 1930s levels but there's one crucial rider - that's as a share of national income which is, of course, massively higher than back then. What's more, the share of GDP taken by spending was almost as low in the year 2000 when both Eds worked in the Treasury. As I recall the NHS still existed back then.

Once again, though, what will matter is the impression left with the electorate.

My job in the next few months will be try to separate the facts from the claims and the spin.